Abstract
Two bacterial strains, YZYP 306(T) and YZGP 509, were isolated from the halophyte Suaeda aralocaspica collected from the southern edge of the Gurbantunggut desert, north-west China. Cells were Gram-stain-positive, aerobic, non-motile, short rods. Strain YZYP 306(T) grew at 4-40 degrees C, while strain YZGP 509 grew at 4-42 degrees C, with optimum growth at 28 degrees C, and they both grew at pH 6.0-12.0 and 0-15 % (w/v) NaCl. Phylogenetic analyses of the 16S rRNA gene sequences placed the two strains within the genus Microbacterium with the highest similarities to Microbacterium indicum BBH6(T) (97.8 %) and Microbacterium sorbitolivorans SZDIS-1-1(T) (97.2 %). The average nucleotide identity value between YZYP 306(T) and M. indicum BBH6(T) was 78.3 %. The genomic DNA G+C contents of strains YZYP 306(T) and YZGP 509 were 68.49 and 68.53 mol%, respectively. The characteristic cell-wall amino acid was ornithine. Whole-cell sugars were galactose, mannose and ribose. The acyl type of the peptidoglycan was glycolyl. The major cellular fatty acids were anteiso-C-15:0, anteiso-C-17:0 and iso-C-16:0. The major menaquinones were MK-10 and MK-11. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, an unidentified phospholipid and an unidentified glycolipid. These results are consistent with the classification of the two strains into the genus Microbacterium. On the basis of the evidence presented in this study, strains YZYP 306(T) and YZGP 509 are representatives of a novel species in the genus Microbacterium, for which the name Microbacterium suaedae sp. nov. is proposed. The type strain is YZYP 306(T) (=CGMCC 1.16261(T)=KCTC 49101(T)).